Phosphorus sources in organic diets for fingerlings and juveniles of Nile tilapia

Abstract

The objective of this work was to evaluate phosphorus sources in organic diets for fingerlings and juvenile Nile tilapia. The experimental design was a completely randomized block, with three treatments: fish waste meal, dicalcium phosphate, and their combination, with six replicates. Two hundred and seventy fingerlings and 180 juveniles were divided into experimental tanks of 250 and 500 L, respectively, and fed diets based on ingredients from certified organic origin containing 32 and 28% crude protein, respectively. Quality of water for cultivation, production indexes and proximate composition of fish carcass were evaluated. Phosphorus sources did not influence the evaluated parameters in fingerlings. Juveniles fed the diet containing fish waste meal had better biological indexes, compared to dicalcium phosphate and did not differ from their combination. The values of phosphorus in the water were above the recommended by the Resolution 357/2005 from Conama. For fingerlings, it is appropriate to use fish waste meal, dicalcium phosphate or its combination as the main source of phosphorus, and, for juveniles, it is appropriate to use fish waste meal or its combination with dicalcium phosphate in organic diets for better production performance.